


The Devil Within

by socksaregoodshit



Category: Haikyuu!!
Genre: Angst with a Happy Ending, Fluff Bomb, HA GUESS WHO'S BACK WITH ANGST, Hurt, Hurt and comfort, Like, M/M, Major Character Injury, ayyyy wouldn't be me without it, fluff at the end, send help, the angst didn't get me; the fluff did
Language: English
Status: Completed
Published: 2018-05-20
Updated: 2018-05-20
Packaged: 2019-05-09 04:25:02
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 4,097
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14709050
Author URL: https://archiveofourown.org/users/socksaregoodshit/pseuds/socksaregoodshit
Summary: “How long has it been?” The usually light and jovial voice crooned, his body shifting ethereally.Suddenly Iwaizumi was transported back to those nights he’d wake up with fever stung skin, drawing ragged breaths through his teeth as he was scarred by the black magic and the voice of his friend now lifeless and full of hatred for the world where there was once a deep-rooted love for life.No.“It’s been five years.” He finally responded, closing his eyes to steady himself, his mind swimming between the past and the present.This wasn’t his friend.





	The Devil Within

**Author's Note:**

> Woooo so I'm living for writing oneshots right now, can you tell?
> 
> It's just past 1:30am here, my heart hurts and tbh I haven't bothered with proofreading and editing, my bed is calling for me.
> 
> But anyways, enjoy the angst!

The guild hall was in ruins.

Iwaizumi and the other mages looked around in disbelief and fear.

The walls were stained red with blood, black with the pressure of the black magic incessantly bearing down on them.

“Iwaizumi-san…”

“I can feel it.” Iwaizumi confirmed, the unspoken question being answered. “It’s here.”

The mages tensed, the air growing thicker as a distortion of black smoke that was almost a solid entitybegan oozing from the walls. It moulded not unlike a liquid, but it held a form; a mass solid enough to be seen.

It grew thicker, almost as if it was breathing as it leaked from the cracks in the broken walls, gathering along the walls and narrowing their footpath.

“It knows we’re here.” Iwaizumi said, only daring to glance at his team. “Stay aware; don’t trust anything. This isn’t the home we use to have.”

“It’s corrupt.” The pinkette beside him supplied as his stance grew guarded.

“Are you ready?” Iwaizumi asked, receiving pensive nods and quiet confirmation in the form of grunts.

So they pressed on.

The black sludge became more frequent; thicker, taking on shapes that mimicked their fallen comrades. Iwaizumi could feel the hairs on the back of his neck standing on end, his body becoming steeped with adrenaline as he prepared himself for the oncoming battle, but no attacks came.

“Where do you think it’ll be?”

“I don’t know,” his side burned, the scarred, tainted skin of his ribcage igniting his nerves, his hand slapped over the smooth, now blackened tissue and he hissed as he struggled to remain standing, “but it’s close.”

The mages exchanged glances behind him, worry and their individual fears coming to light at the sight of their mainstay being beaten down by a wound inflicted years prior.

They all remained aware, wary of the smallest movement, the smallest sounds catching their attention; but never fully, to become totally distracted was to hand their life over to the entity that had been among them all as their friend until the fateful night now known as The Rejection.

When their purest paladin rejected the white magic and aid of his friend.

When everything changed.

They continued down the corridor, following the oozing secretion and hoping this wasn’t another one of its tricks.

As they passed a long wall mirror, Yahaba chanced a glance into the dusted, broken glass, a shadow of his former teacher flashing into his own shattered reflection and he startled, dropping his staff with a clatter on the marble floor.

The sound echoed around them, the walls seemingly constricting as they all reacted to the sudden, unexpected noise.

“Shit.” He cursed alongside his fellow mages as they all recovered from the scare. He grabbed the spell-casting weapon and held it close with both hands, his left hand running through the previously unnoticed black slime now covering the underside of the staff.

He barely had time to react, looking at his palm and the necrosis spell already beginning to eat at his protective magic barrier, wearing it down and shocking him to his core as it penetrated his magic and took root in his skin.

“I—Iwaizumi-san!”

The group turned, only able to watch in horror as his hand was turning black, tainted by the same dark magic as Iwaizumi all those years ago.

Iwaizumi noticed it instantly, how Yahaba’s veins turned black under his skin, travelling up his arm at a frightening pace.

“Yahaba!”

Suddenly the mage stopped his struggling, arm falling to his side.

 _“Did you honestly come here to stop me?”_ It questioned through his friend.

Iwaizumi’s heart clenched and his stomach lurched.

That voice.

It hadn’t changed.

“Oi—”

 _“I’ll spare him this time,”_ a cruel chuckle, _“so long as you can beat me, that is. If you can’t then they all die; I’ll destroy them in front of you.”_

Before Iwaizumi could respond to the taunting voice he heard a choked shout from beside him.

Hanamaki.

Imbedded within his friend’s neck protruded a morphing, pulsing blackness that had pierced his barrier and skin with controlled ease.

Hanamaki’s eyes were wide, his body showing panic for only seconds before he too went limp.

 _“I could spare both of them.”_ The voice echoed this time, two of his friends reciting the same words. It was taunting him, showing only an inkling of its true power.  _“But you could leave with your life at the expense of theirs.”_

“Like that’s even a question!” Iwaizumi roared, unsure where to look with two of the seven people at his side taken over. “I—”

_“But do your allies feel the same?”_

Iwaizumi winced, chancing a glance at the obviously scared group of mages.

“Is there a fourth option?”

That cruel laugh sounded once more from the voice box of his long-gone friend.

_“It depends on how entertaining it is.”_

“Me for them.”

The group of mages looked up from their own troubled and muddled thoughts to look at Iwaizumi. Much to the creature’s amusement if his friends distorted face were anything to go by.

“Iwaizumi, no!” Matsukawa growled, gripping his friend’s shoulder and pulling him back.

“But—”

“No way are we willingly gonna let you go in there so we can escape.” Matsukawa’s brows were furrowed tightly, conviction overriding his fear. “You already tried that once; learn from it!”

Stern eyes met his, Kyoutani’s eyes boring into his own, Kindaichi, Kunumi, and Watari all wearing matching expressions.

 _“Do you all wish to remain and fight me?”_ A cocky sneer that didn’t match the voice or faces it was projected onto.

Iwaizumi looked around him one last time, they were all scared, clenched teeth and tense shouldered. But they weren’t going to give up without a fight and to deny them that wasn’t his place.

“Yes.”

_”Very well.”_

The blade melted away from Hanamaki’s neck, the left side of his face still tinged with black veined patterns, Yahaba’s hand and arm in a similar state as the black on his hand dripped onto the floor before moulding into a viscous shape once more and Iwaizumi watched as it crept along the floor.

“That was horrible.” Hanamaki winced, rubbing over the entry site.

Yahaba remained quiet, holding his staff with a rigid posture, likely afraid to touch the sludge again.

He heard the group asking with concerned voices, checking their friends over as his eyes continued to follow the gelatinous creature.

“Lets follow it.” He declared.

“Are you nuts?” Kyoutani growled. “What if there’s more of that stuff around the corner?”

“Then that means we’ve got the right direction.”

Without another word of objection the group followed Iwaizumi further into the guild, and it quickly became clear where they were heading.

The original hunch everyone had was confirmed as they reached the heavy oak doors.

Or what was left of them.

Iwaizumi sucked in a breath as he saw the decayed, festering ruins of what was once the entrance to the grand hall.

The doors were thick with the same black mass as throughout the guild, only this time it was thicker than tar and the density of darkness looked like a void in comparison to the earlier charcoal.

“Are you all ready?” Iwaizumi asked, waiting for confirmation before he risked his own safety to push on the doors.

Nothing could’ve prepared him for the sight, or sensation of entering the hall.

None of them were prepared.

Upon a bed of rubble sat the creature they’d demonised.

 




_“Iwa-chan!”_

_“What is it, Shittykawa?”_

_“Rude!”_




 

His skin was pale; almost translucent, the deep black lines scorching his skin as the venom of the beast thrummed its well-known tune in his veins. His eyes were hollow, casting a glance of disregard to the group of mages.

Iwaizumi’s chest stung as he stared back at those blank eyes.

The hands of his friend gripped the rubble, skin so whitewashed his knuckles didn’t whiten as he did so. He stood, using the topography he’d created to stand above them, looking down his nose at the group.

“How nice of you to join me.” He sneered. “I’ve been lonely.”

By now Iwaizumi’s body was screaming in protest, his tainted skin burning white-hot. Iwaizumi struggled against the black tendrils of unconsciousness licking at his mind; it was almost enticing, after so long to just...surrender.

But for five years he’d been pursuing the beast that had taken his dearest friend from him.

And now his friends’ lives were hanging in the balance as well.

Like hell would he give up with his goal so close to being accomplished.

“How long has it been?” The usually light and jovial voice crooned, his body shifting ethereally.

Suddenly Iwaizumi was transported back to those nights he’d wake up with fever stung skin, drawing ragged breaths through his teeth as he was scarred by the black magic and the voice of his friend now lifeless and full of hatred for the world where there was once a deep-rooted love for life.

No.

“It’s been five years.” He finally responded, closing his eyes to steady himself, his mind swimming between the past and the present.

This wasn’t his friend.

This was a creature who couldn’t be saved, couldn’t be cleansed.

It needed to die.

It only wore the face of his friend.

 




_“Iwa-chaaan~~” His beaming smile caught Iwaizumi off guard, he heart hammering in his chest._

_“Oh, so you can smile genuinely.”_

_“Excuse you? Of course I smile genuinely! I genuinely smile all the time!”_

_They both knew this was a lie, but it was a harmless one. Oikawa’s smiles were rarely genuine, Iwaizumi only being privy to those slight quirks of his lips as he engaged with things he was passionate about or found amusing._




 

Iwaizumi watched in horror as his friends were stuck down, one by one they fell as the creature continued its onslaught, he felt his breath escaping his lungs in harsh gasps, catching in his throat.

“If you remember correctly, I did say a fight between me and you.” The beast jeered with a laugh that should’ve been light and airy, instead it was dark and crusted with poison. “Brace yourself, _Iwa-chan_.” It broke up each syllable, lunging as Iwaizumi froze in place from the suddenness.

 




_“Brace yourself, Iwa-chan!” The eager, innocent excitement was infectious and Iwaizumi soon dropped his teasing lilt._

_“Yeah, yeah, what’s up?” Iwaizumi fought the warmth in his face as Oikawa’s arms wrapped around his shoulders and he was presented with a palm-up hand cradling a small, immature ball of light._

_“I can do it, Iwa-chan!” His grin was wide, proud of himself._

_It was tiny, nearly no accomplishment at all to a skilled mage, to himself born from a long line of high ranked paladins._

_But for Oikawa? It was a ground-breaking accomplishment._

_Someone with hardly any magically power, in a world of those who oozed it, were geniuses and utilised it all to their best ability. His first successful spell was the beginning of a life-long struggle to keep up, keep growing, to become the best._

_But he didn’t see the struggle, he saw his achievement._

_“That’s great, Tooru,” he remembered speaking softly to his friend, admiration lacing his tone, “but I bet you can’t get it any bigger!”_

_Because Oikawa needed the challenge in order to succeed._

_“I bet I can!”_

_“Prove it.”_

_“Just you wait, Iwa-chan!”_

_It turned out Iwaizumi didn’t have to wait much longer. He could feel a dormant storm within his friend’s aura growing with each day, it was only small, but it was there._

_But it was different; much different to his own._

_However, his friend was happy and everything had been fine so far._

_It’d be okay, right?_




 

Blood sprayed across his face; warm and he suddenly became far too aware of his surroundings.

The stone floor beneath him, cold and hard, chilling him as he bled out.

Cries from his friends that were still conscious muffled by the sound of his blood pounding in his ears.

Oh, it was his blood.

His neck stung and the pain made his vision blur and scatter.

“Shit…”

He used is broadsword to hold himself up, but it was futile and he soon found himself on the floor, kneeling with his head bowed.

“It’s a shame that you all have to die here, really; it truly is.” The creature sneered, walking over to the body closest to Iwaizumi’s. Kunumi. “But you've lost, and now you must watch them die.”

Iwaizumi could feel his consciousness fading, vision becoming tunnelled.

No.

This couldn’t happen.

_Dammit!_

“I’m not finished yet!” He spat, glowering up at the creature with his friend’s form and for a moment he no longer felt it was hopeless.

That was until a hand gripped the collar of his undershirt, lifting him from the ground and reminding him of their power difference.

“You’re very finished, look at you.” He was thrown back, his head hitting one of the twelve pillars and he groaned as his vision swam further.

A cold hand clasped his ankle, dragging him along the floor towards a waiting beast.

He flung his arm outwards and a wave of fire radiated towards his attacker and causing him to stagger back.

“Ahah, you still have some fight, paladin?” It scoffed condescendingly.

“Of course.” Iwaizumi couldn’t resist the grin that spread onto his lips. He'd always lived for a fight. “Try me, beast.”

“Very well.”

Everything moved to fast after that; or too slow, Iwaizumi’s mind unable to register what was going on either way.

He guessed the blood loss had finally taken a firm grasp on his body.

But as the beast lunged his body reacted in the only way it knew how.

He felt the pressure on his blade; a body falling onto the wide broadsword. It ran deep into Oikawa’s chest, deep into his heart.

There seemed to be no struggle, the body of his friend going limp and he took a shaky breath as sanguine beads dropped onto his face from Oikawa’s mouth, his hands growing sticky with the same rapidly cooling liquid.

It was his fault.

Deep down he’d always known; it was his fault.

The creature within Oikawa, laying dormant yet lending him its power like a leaking faucet had responded to his magic all those years ago.

It was his fault... 

 




_It was the night before Oikawa’s coronation as the new leader of the council, the brunette approaching him with a problem; an “ill feeling” Oikawa had called it._

_“Iwa-chan, I need you to cleanse my aura; there’s something wrong and it’s making me feel awful when all I want to do is enjoy my coronation tomorrow!” He’d dramatically announced._

_“I can’t feel anything wrong with your aura,” Iwaizumi reasoned, that was his speciality, after all, “what makes you think it’s not a physical ailment?”_

_He noticed the redness high up on Oikawa’s cheekbones as the latter pouted._

_Maybe he was ill._

_“Iwa-chan, please!” Oikawa huffed, crossing his arms over his chest. “I know this isn’t a physical problem, I think my heart gate might be blocked or something, it doesn’t feel right lately.”_

_His heart gate was definitely fine._

_But if he wanted to be cleansed then what could go wrong?_

_“Alright, give me five minutes.” He stood from his sitting position, walking over to his cabinet with his cleansing equipment._

_“Thank you~”_

_He rooted inside the unit and removed what he needed, setting up his cleansing casting circle so he could stop his friend’s flapping._

_Oikawa stepped inside and once again, under what was essentially a magnifying glass for finding issues with someone’s magic or aura, there was nothing unusual for Oikawa._

_But the inkling of power that was there wasn’t normal for anyone other than Oikawa._

_What if that was it?_

_That something was causing Oikawa’s ailment?_

_He shouldn’t touch it._

_That was the source of Oikawa’s magic._

_“C’mon, Iwa-chan! I gotta practice my speech some more.”_

_But he did it anyway; and it cost him dearly._

_He watched as his white magic became engulfed by darkness, his friend’s cries sounding through the late Spring skies as his back split open and an oozing black mass hovered and established itself around Oikawa’s form. Globules erupted into the air and seared everything they touched, taking root like a weed and spreading like wildfire._

_It consumed everything in seconds, Oikawa’s cries of pain never lessening and Iwaizumi could do nothing other than watch._

_He couldn’t react fast enough as his casting circle shattered, shards of black-tinged white magic cutting into his skin as a precursor to the larger attack he was then victim to._




 

“Iwaizumi!” Came Hanamaki’s broken, hoarse cry as he scrambled to his feet.

Iwaizumi felt a brief sense of relief at the fact his friend was alive; even if he died now alongside Oikawa. At least they wouldn’t.

He looked up at Oikawa’s form, impaled and broken on his weapon, a wave of nausea and grief pouring over him.

Matsukawa joined Hanamaki, struggling with his own injuries and lifting Oikawa’s form from the over-sized blade.

Iwaizumi instantly let go of the lumbering item, the adrenaline finally leaving his body and his arms collapsing on either side of him.

“Shit…” He gasped, looking to his right where Hanamaki and Matsukawa had positioned Oikawa.

 




_“Dammit! Where is he?” Iwaizumi cried, feeling the gurgle in his chest of blood filling his lungs, the near-fatal wound under his ribs needing urgent treatment he just didn’t want to stay still for._

_“Iwaizumi stop!” Hanamaki cried with teary eyes and shaking hands. “Mattsun!”_

_He continued to struggle; struggling against Hanamaki; against himself wanting to chase Oikawa, knowing he needed medical help; struggling against succumbing to the near-fatal wound._

_He needed to do something._

_But he didn’t know where to start._

_What the hell was that?_




 

“Iwaizumi, stay with us!” Hanamaki’s frantic voice called through a haze of barely-conscious thoughts and memories.

It was a mirror of five years before.

He never wanted to be in the position again.

Close to dying by his friend’s hand all over again.

He choked on a cough.

_Fuck._

He looked to his right again, seeing the messy nest of brown hair, long eyelashes on black and white striped skin.

Oikawa wasn’t mean to look that way.

Before he knew it voices of his friends faded into white noise, his breath hitching and his consciousness finally fading.

“I—”

 




_Physical recovery took a long time._

_Mental recovery never really happened._

_He was obsessed with finding Oikawa, bringing Oikawa back alive, he desperately wanted his friend back._

_He felt guilt for not admitting how he felt about Oikawa before he made that fatal mistake._

_The mistake that destroyed them both; set the wheels of fate into motion._

_He trained, he researched, he practiced his technique._

_Eventually he found what he needed, was able to create a new spell and infuse the magic into his sword. He learned the technique that would, in theory, bring back his friend, to save him._

_It took years, four and a half from The Rejection._

_But then doubt crept in._

_If this creature was giving Oikawa its power; to remove that entity would remove Oikawa’s power._

_Did he really want that?_

_Someone who wasn’t naturally gifted with the promise of success, would he really give up the success he’d earned by hard work alone?_

_“Iwaizumi, are you ready?”_

_He looked up from the make-shift desk in the less-than-stellar make-shift guild hall, seeing Hanamaki and Matsukawa at his door._

_“Ready for what?”_

_“To get Oikawa back, of course.” Matsukawa smirked lazily._

_“Are you sure?”_

_“We all are.” Hanamaki’s voice was softer than normal; supportive rather than cynical._

_Iwaizumi looked behind them, counting a further five heads of hair._

_He was lucky._

_“Yeah,” he mumbled, closing his eyes before repeating his resolve, “yeah, let’s bring him back.”_




 

A sensation against his hand brought Iwaizumi to semi-awareness.

He opened his eyes, only realising at the sight of his surroundings that he wasn’t just waking up in his room.

He'd just fought with Oikawa.

His throat was cut.

He wasn’t dead?

The gentle pressure on his hand made him crane his still sore neck to his right.

Oikawa.

The brunette’s head had moved since the last time, his whole body had.

It was now curled up on itself, knees tucked up to his chest and head lowered below his shoulders.

But his fingers clung to Iwaizumi’s hand like he was afraid he’d disappear if he let go.

“Oi—”

“Relax, Iwaizumi,” Matsukawa muttered, it was then that Iwaizumi felt the warmth invading his body and he relaxed, welcoming it, “your throat is still pretty torn up. His body is no better now he no longer has an aura.”

“What…?” Iwaizumi felt like his heart slammed into his ribcage. “No aura?”

A hum.

“As of this moment his aura is gone, depleted or non-existent I don’t know, but right now he’s a normal human.”

“But…he is alive, right?”

A pause, Matsukawa’s lips quirking just slightly.

“He is.” He closed his eyes. “Well done.”

“What about everyone else?”

“Superficial abrasions and shallow cuts; otherwise fine.”

“Thank God.”

“Nah, thank yourself.”

Iwaizumi looked to Oikawa’s prone form, unable to hold back his smile. He was alive.

He squeezed the hand holding onto his, allowing himself to succumb to his exhaustion. Five years’ worth of it.

 




_He didn’t know when the feelings began, just that they were there one day and he couldn’t exactly say he didn’t want them to be._

_It felt like a river, how it’s course changes so naturally and weaves and meanders, growing evermore intricate yet never changing its fundamental purpose._

_He’d loved Oikawa for far longer than he thought was possible, and just like a river those feelings had grown and changed with their environment._

_He wondered if there was such a thing as soulmates, but Oikawa was clearly oblivious to his feelings so he found it hard to believe—to hope for such a thing._

_But that didn’t matter, he was happy so long as he was at his side._




 

“Iwa-chan! Iwa-chan, look!”

Iwaizumi looked up from the hardwood desk in the council chambers, as the leader he’d been working nonstop to repair their broken guild hall and all the services the building offered. They'd already rebuilt the land around the hall, a once bustling city rebuilt from its ashes and prospering.

He felt his heart become still as he looked to the man before him, wide and innocent eyes glimmering with light and love, black veins taking their time to fade from his complexion but his pale skin regaining its healthy tan anyway.

“Yeah?” He asked, placing his pen on his desk and giving Oikawa his undivided attention.

“Watch this!”

Iwaizumi watched, watched as the ball of energy manifested in his palm; the first magic Oikawa had summoned in two years, since the night The Rejection was reversed.

“I knew you could do it, Tooru.” He spoke reverently, watching the taller man get so excited over the prospect of his powers returning.

New powers _growing_.

“I’m proud of you.”

A blinding smile.

“Thanks, Iwa-chan!” The magic disappeared, a thin sheen of sweat on Oikawa’s brow. “Wanna go get lunch?”

Iwaizumi felt contentment sweep over him.

“Sure, lunch sounds good.” He stood from his desk, grabbing his official jacket from the back of his seat and swinging it over his shoulder, one finger hooked into the collar. “Ready?” He offered his free arm to Oikawa.

“Ready!” The latter grinned with determination, gripping his bicep and linking his own through the crook of his elbow.

They made their way out of Iwaizumi’s office, down into the corridors and then into the luscious gardens now growing around the guild hall.

For a moment Iwaizumi was struck with awe, how far they’d fallen, how far they’d crawled back up.

Together.

A soft smile toyed at his lips, watching Oikawa’s enraptured face as he gushed over the floral choices he’d made and how they _fit the garden perfectly, Iwa-chan!_

He was overcome by emotions as he realised just what made him feel the way he did about his best friend.

His love for life.

His willpower.

His courage.

The list was far too long for Iwaizumi to recite in his mind without repeating one or two of the things he loved the most.

So he didn’t try, he just enjoyed it.

“I love you.”

“Iwa-chan!” Oikawa gasped.

That noise he made whenever Iwaizumi said something he wasn’t expecting; a brutally honest squawk of a noise.

He loved it.

“I love you.”

**Author's Note:**

> Find me on [Tumblr](https://www.tumblr.com/blog/i-am-a-bit-of-a-crank)


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